List of Illustrations. xi 



Fia. PAOE 



81. Larvae of : Star-fish, Ophiurid, Sea-urchin, Holothurian . 127 



82. Bhuocrinus lofotensis . . . ... . . 128 



83. Aniedon . . . . .128 



84. Ventral surface of Antedon .... . . . 128 



85. LarvEB of Antedon rosacea ... . . 129 



86. Aniedon BschrichUi ... ... ... 129 



87. Diagrammatic figures explaining the structure of a Star-fish . .132 



88. Diagram explaining the structure of an Ophiurid . . 133 



89. Shell of a Regular Sea-urohiu 135 



90. Shell of an Irregular Sea-urchin . . 135 



91. Diagrammatic longitudinal section of the spine of a Sea-urchin . 137 



92. Diagram of a Holothurian , 139 



93. Transverse section of the body-waU of a Holothurian . . 139 



94. Transverse section through a radius of the body- wall of a Holothurian . 139 



95. Nervous system of Sistomum ... . 142 



96. Part of the excretory system of a Klatworm . 142 



97. Longitudinal section through Cyoloporus papUlosus . . 143 



98. Sketch of Mesostomwin splendidwn. . 144 



99. Sketch of Provortex aff/nis ... . 144 



100. Planaria lactea . , ... . 145 



101. Larva of a marine Turhellarian . . . . 145 



102. Sketch of Liver-fluke .146 



103. Diploeoon paradoxum . . . . 147 



104. Distomum hepaticum . . 148 



105. Polystomum integerrimum .... . . . 149 



106. Snail with Leuooohloridium in both tentacles . 149 



107. Tssnia mediocanellata . 149 



108. Six hooked larva of T. soJiMm . . . 150 



109. Proscolex of the same ... . . . , 150 



110. Ciliated larva of Bothriocephalus latus ... . 150 



111. Proscolex of the same . . ... 150 



112. Head of Tcenia solium (A), of T. mediocanellata (B), and of Bothrio- 



cephalus latus (0) . ... 152 



113. Taenia echinococcus ... . . 152 



114. Bothriocephalus latus . 153 



115. Sketches of a Nemertine .... 154 



116. Diagrammatic section of a Nemertine . 155 



117. Three larval stages of a Nemertine ... . . 155 



118. J., diagram of a female Rotifer : B, the male ... . . 156 



119. Transverse section of a Nematode . . . 158 



120. Hind end of a male Nematode 159 



121. Intestinal Trichina ... 161 



122. Muscle Trichina . . . 161 



123. Dochmius duodenalis . 161 



124. Filaria m^dinensis . . 161 



125. Heterodera Schachtii . ... 163 



126. Echinorhynchus . 164 



127. Larva of an Acanthocephalon . . . 164 



128. An Annelid seen from the side . . 165 



